The disclosed embodiments generally pertain to gas turbine engines. More particularly, but not by way of limitation, present embodiments relate to drains for gas turbine engine sumps.
In a gas turbine engine a typical gas turbine engine generally possesses a forward end and an aft end with its several core or propulsion components following axially therebetween. An air inlet or intake is at a forward end of the engine. Moving toward the aft end, in order, the intake is followed by a compressor, a combustion chamber, a turbine, and a nozzle at the aft end of the engine. It will be readily apparent from those skilled in the art that additional components may also be included in the engine, such as, for example, low-pressure and high-pressure compressors, and high-pressure and low-pressure turbines. This, however, is not an exhaustive list. An engine also typically has an internal shaft axially disposed along a center longitudinal axis of the engine. The internal shaft is connected to both the turbine and the air compressor, such that the turbine provides a rotational input to the air compressor to drive the compressor blades.
In operation, air is pressurized in a compressor and mixed with fuel in a combustor for generating hot combustion gases which flow downstream through turbine stages. These turbine stages extract energy from the combustion gases. A high pressure turbine first receives the hot combustion gases from the combustor and includes a stator nozzle assembly directing the combustion gases downstream through a row of high pressure turbine rotor blades extending radially outwardly from a supporting rotor disk. In a two stage turbine, a second stage stator nozzle assembly is positioned downstream of the first stage blades followed in turn by a row of second stage rotor blades extending radially outwardly from a second supporting rotor disk. The turbine converts the combustion gas energy to mechanical energy.
In known turbine engines, the rotor shaft is typically supported for rotation by utilizing aft bearing assemblies. These bearing assemblies are lubricated and cooled through the use of separate oil sump systems.
It is always desirable to decrease the weight of a gas turbine engine utilized in the aviation industry. Such weight reduction results in higher efficiency of the engine and improved efficiency save cost for operators. It is also desirable to decrease the number of parts in a turbine engine which improves manufacturability and also improves the efficiency aspects previously noted. Certain engine designs have reduced engine weight by removing frame members or strut features. However, while meeting the goal of weight reduction, the changes also affect oil routing through the engine.
More specifically, extreme attitude angle or position, for example nose up condition, can affect the flow of oil through what are otherwise gravity drains. Longer axially extending runs of oil ducting may become problematic. In failure condition of a bearing sump seal, drains provide movement and removal of oil from a bearing sump. If a failure occurs and a plane is at an extreme attitude position, portions of the drain pathway may require movement of oil vertically through a path, tubing or fittings. When oil cannot move upwardly due to the vertical elevation, the oil may overflow into areas of higher temperature causing fire or coking components of the turbine engine.
As may be seen by the foregoing, it would be desirable to overcome these and other deficiencies with gas turbine engines.